Tissue Plasminogen Activator (tPA)
Definition
A serine protease secreted by endometrial cells and vascular endothelium that converts plasminogen to plasmin. Elevated in menstrual blood relative to peripheral blood, driving the characteristic non-clotting property.
- Type
- Serine protease
- Source
- Endometrial cells and vascular endothelium
- Action
- Converts plasminogen to plasmin
- Forensic relevance
- Elevated in menstrual blood, drives non-clotting property
Common questions
How does tPA help distinguish menstrual blood from peripheral blood in casework?+
Because tPA activity is markedly higher in menstrual blood, it keeps that blood from clotting the way peripheral blood does. Assays or observations sensitive to this fibrinolytic activity can support distinguishing a menstrual bloodstain from an injury bloodstain.
Is a non-clotting bloodstain always menstrual blood?+
No. Other factors such as the surface the blood dried on, dilution, or conditions like haemophilia can also affect clotting appearance, so tPA-related non-clotting behaviour is corroborating evidence, not a standalone identification of menstrual origin.
Related terms
- D-Dimer
- A fibrin degradation product generated when cross-linked fibrin is cleaved by plasmin. Elevated D-dimer in menstrual blood reflects the active fibrinolytic process;...
- Endometrial Shedding
- The physiological process by which the functional layer of the uterine endometrium is broken down and expelled during menstruation. The shedding process...
- Fibrinolysis
- The enzymatic breakdown of fibrin by plasmin, which is generated from plasminogen by tissue plasminogen activator (tPA). Menstrual blood has high tPA...
- Matrix Metalloprotease 10 (MMP-10)
- An endopeptidase of the MMP family involved in extracellular matrix remodelling during endometrial breakdown and shedding. Significantly elevated in menstrual blood and...
- mRNA Profiling
- Detection of messenger RNA transcripts specific to particular tissues or body fluids. Endometrial-specific transcripts (LEFTY2, MMP-10 mRNA, others) can distinguish menstrual blood...